安卓作业----用安卓创建一个计算器，完成基本的加、减、乘、除四则运算
1. 完成界面如下实现代码1. MainActivity.javaimport android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.Button;import ...
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这是中国大学慕课移动终端应用开发的网课作业3，我会持续更新我的作业，如果有需要关注一下吧
因为要求的是简单的加减乘除，并没有需要更高的要求，所以功能比较简单，页面主要照着课程要求来的。如果需要了解更优的方法实现计算器，可以参考利用二叉树前中后续遍历实现计算器，此计算器有bug可私信我
1. 完成界面如下
实现代码
1. MainActivity.java
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
private Button mButtonAdd,mButtonJian,mButtonCheng,mButtonChu,mButtonEqual;
private TextView mTextViewQuestion,mTextViewResult;
private String questionShow = "";
private String questionGet = "";
private double numberA;
private double numberB;
private int symbol = 0;
private boolean flag = false;//记录有没有重复写入运算符
private void init(){
mButtonAdd = findViewById(R.id.buttonAdd);
mButtonJian = findViewById(R.id.buttonJian);
mButtonCheng = findViewById(R.id.buttonCheng);
mButtonChu = findViewById(R.id.buttonChu);
mButtonEqual = findViewById(R.id.buttonEqual);
mTextViewQuestion = findViewById(R.id.questionText);
mTextViewResult = findViewById(R.id.resultText);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
mButtonAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (questionGet==""||flag){
Toast.makeText(MainActivity.this,"不符合计算规则",Toast.LENGTH_SHORT).show();
}else {
numberA = Double.parseDouble(questionGet.toString());
questionGet = "";
questionShow +="+";
symbol = 1;
flag = true;
mTextViewQuestion.setText(questionShow);
}
}
});
mButtonJian.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (questionGet==""||flag){
Toast.makeText(MainActivity.this,"不符合计算规则",Toast.LENGTH_SHORT).show();
}else {
numberA = Double.parseDouble(questionGet.toString());
questionGet = "";
questionShow +="-";
symbol = 2;
mTextViewQuestion.setText(questionShow);
flag = true;
}
}
});
mButtonCheng.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (questionGet==""||flag){
Toast.makeText(MainActivity.this,"不符合计算规则",Toast.LENGTH_SHORT).show();
}else {
numberA = Double.parseDouble(questionGet.toString());
questionGet = "";
questionShow +="*";
symbol = 3;
flag = true;
mTextViewQuestion.setText(questionShow);
}
}
});
mButtonChu.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (questionGet==""||flag){
Toast.makeText(MainActivity.this,"不符合计算规则",Toast.LENGTH_SHORT).show();
}else {
numberA = Double.parseDouble(questionGet.toString());
questionGet = "";
questionShow +="/";
symbol = 4;
flag = true;
mTextViewQuestion.setText(questionShow);
}
}
});
mButtonEqual.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (questionGet==""){
Toast.makeText(MainActivity.this,"无计算任务",Toast.LENGTH_SHORT).show();
}else {
numberB = Integer.parseInt(questionGet.toString());
double result = 0;
if (symbol==1){
result = numberA + numberB;
}else if (symbol == 2){
result = numberA - numberB;
}else if (symbol == 3){
result = numberA * numberB;
}else if (symbol == 4){
if (numberB!=0){
result = numberA/numberB;
}else {
Toast.makeText(MainActivity.this,"除数不可为0",Toast.LENGTH_SHORT).show();
}
}else {
Toast.makeText(MainActivity.this,"无计算任务",Toast.LENGTH_SHORT).show();
}
mTextViewResult.setText(result+"");
numberA = 0;
numberB = 0;
symbol = 0;
questionShow = "";
questionGet = "";
flag = false;
}
}
});
}
//单机数字事件
public void bindTapNumber(View v){
switch(v.getId()){
case R.id.button0:
questionShow +="0";
questionGet +="0";
mTextViewQuestion.setText(questionShow);
break;
case R.id.button1:
questionShow +="1";
questionGet +="1";
mTextViewQuestion.setText(questionShow);
break;
case R.id.button2:
questionShow +="2";
questionGet +="2";
mTextViewQuestion.setText(questionShow);
break;
case R.id.button3:
questionShow +="3";
questionGet +="3";
mTextViewQuestion.setText(questionShow);
break;
case R.id.button4:
questionShow +="4";
questionGet +="4";
mTextViewQuestion.setText(questionShow);
break;
case R.id.button5:
questionShow +="5";
questionGet +="5";
mTextViewQuestion.setText(questionShow);
break;
case R.id.button6:
questionShow +="6";
questionGet +="6";
mTextViewQuestion.setText(questionShow);
break;
case R.id.button7:
questionShow +="7";
questionGet +="7";
mTextViewQuestion.setText(questionShow);
break;
case R.id.button8:
questionShow +="8";
questionGet +="8";
mTextViewQuestion.setText(questionShow);
break;
case R.id.button9:
questionShow +="9";
questionGet +="9";
mTextViewQuestion.setText(questionShow);
break;
}
}
}
2. activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="@+id/questionText"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="2"
android:text="0"
android:gravity="right"
android:layout_gravity="bottom"
style="@style/question"/>
<TextView
android:id="@+id/resultText"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="3"
android:gravity="right"
android:text="0"
style="@style/result"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_weight="15"
android:paddingTop="2dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="80dp"
android:orientation="horizontal">
<Button
android:id="@+id/button7"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="7"
android:onClick="bindTapNumber"
style="@style/number"/>
<Button
android:id="@+id/button8"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="8"
android:onClick="bindTapNumber"
style="@style/number"/>
<Button
android:id="@+id/button9"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="9"
android:onClick="bindTapNumber"
style="@style/number"/>
<Button
android:id="@+id/buttonChu"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="/"
style="@style/symbol"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="80dp"
android:orientation="horizontal">
<Button
android:id="@+id/button4"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="4"
android:onClick="bindTapNumber"
style="@style/number"/>
<Button
android:id="@+id/button5"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="5"
android:onClick="bindTapNumber"
style="@style/number"/>
<Button
android:id="@+id/button6"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="6"
android:onClick="bindTapNumber"
style="@style/number"/>
<Button
android:id="@+id/buttonCheng"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="*"
style="@style/symbol"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="80dp"
android:orientation="horizontal">
<Button
android:id="@+id/button1"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="1"
android:onClick="bindTapNumber"
style="@style/number"/>
<Button
android:id="@+id/button2"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="2"
android:onClick="bindTapNumber"
style="@style/number"/>
<Button
android:id="@+id/button3"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="3"
android:onClick="bindTapNumber"
style="@style/number"/>
<Button
android:id="@+id/buttonJian"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="-"
style="@style/symbol"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="80dp"
android:orientation="horizontal">
<Button
android:id="@+id/button0"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="0"
android:onClick="bindTapNumber"
style="@style/number"/>
<Button
android:id="@+id/buttonEqual"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="2"
android:text="="
style="@style/symbol"/>
<Button
android:id="@+id/buttonAdd"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1"
android:text="+"
style="@style/symbol"/>
</LinearLayout>
</LinearLayout>
</LinearLayout>
3. styles.xml
<resources>
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
<!-- Customize your theme here. -->
<item name="colorPrimary">@color/colorPrimary</item>
<item name="colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="colorAccent">@color/colorAccent</item>
</style>
<style name="textSize">
<item name="android:textSize">30dp</item>
</style>
<style name="number" parent="textSize">
<item name="android:textColor">#000000</item>
<item name="android:background">#F0D7D7</item>
</style>
<style name="symbol" parent="textSize">
<item name="android:textColor">#FFFCFC</item>
<item name="android:background">#FFC67C</item>
</style>
<style name="question">
<item name="android:textSize">20dp</item>
<item name="android:textColor">#A09E9E</item>
</style>
<style name="result">
<item name="android:textSize">45dp</item>
<item name="android:textColor">#000000</item>
</style>
</resources>
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